Jennifer Aniston has revealed she has trouble sleeping at night because she is kept awake by all the thoughts going on in her mind.

The 45-year-old actress confessed her problem with insomnia while appeared on The Dr Oz Show, and admitted having her three pet dogs and fiance Justin Theroux in her bed didn’t make matters any better.

Justin Theroux is engaged to Jennifer Aniston
Jennifer Aniston with fiance Justin Theroux (Evan Agostini/AP)

Jennifer revealed: “I have a hard time sleeping. Sleep is a tough one for me. My brain, the committee in my head, if I wake up at three in the morning I just start having conversations and they won’t shut up and then I can’t get back to sleep. I do have three animals and a human being in the bed, so there are all these distractions.”

She added: “I got an app on my phone that allows you to sort of track your sleep rhythms, like how deep you go. I don’t really quite ever get into the deep, deep, deep sleep. And am I going to die young?!”

The actress also revealed she suffered a lot of discomfort gaining weight for her latest film role – as a woman suffering from chronic pain in Cake.

Jennifer revealed: “It’s interesting when you stop exercising. It really was interesting how my Serotonin levels went down. My stamina was shot. I was cranky. I was irritable. I’m usually really not any of those things.

“I just found myself short. I was hungry like crazy. Then, you realise exercise is just so important to our soul. Not just being able to fit into skinny jeans, just your state of mind, your soul, all of that. I surrendered into it. I actually didn’t fight it. I didn’t think, oh this is horrible. It was such a part of what I enjoyed about mining this character.”